v2.4.0.8
Discontinued Operations and Assets and Liabilities Held for Sale (Assets and Liabilities Table) (Details) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Assets and Liabilities of Discontinued Operations and Held For Sale [Line Items]    
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net   $ 21.5
Disposal Group, Including Discontinued Operation, Other Assets   5.2
Assets of Disposal Group, Including Discontinued Operation 0 26.7
Disposal Group, Including Discontinued Operation, Other Liabilities   3.9
Liabilities of Disposal Group, Including Discontinued Operation 0 3.9
Gas Distribution Operations [Member]
   
Assets and Liabilities of Discontinued Operations and Held For Sale [Line Items]    
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net   21.5
Disposal Group, Including Discontinued Operation, Other Assets   4.5
Assets of Disposal Group, Including Discontinued Operation   26.0
Disposal Group, Including Discontinued Operation, Other Liabilities   3.3
Liabilities of Disposal Group, Including Discontinued Operation   3.3
Electric Operations [Member]
   
Assets and Liabilities of Discontinued Operations and Held For Sale [Line Items]    
Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net   0
Disposal Group, Including Discontinued Operation, Other Assets   0.7
Assets of Disposal Group, Including Discontinued Operation   0.7
Disposal Group, Including Discontinued Operation, Other Liabilities   0.6
Liabilities of Disposal Group, Including Discontinued Operation   $ 0.6